/*
 * Copyright 1999-2006 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package com.googlecode.streamflyer.regex.fast;

import sun.security.action.GetPropertyAction;

/**
 * Unchecked exception thrown to indicate a syntax error in a regular-expression
 * pattern.
 * 
 * @author unascribed
 * @since 1.4
 * @spec JSR-51
 */
@SuppressWarnings({ "serial", "restriction" })
// NEW @SuppressWarnings ADDED BY rwoo
public class PatternSyntaxException extends IllegalArgumentException {

	private final String desc;
	private final String pattern;
	private final int index;

	/**
	 * Constructs a new instance of this class.
	 * 
	 * @param desc
	 *            A description of the error
	 * 
	 * @param regex
	 *            The erroneous pattern
	 * 
	 * @param index
	 *            The approximate index in the pattern of the error, or
	 *            <tt>-1</tt> if the index is not known
	 */
	public PatternSyntaxException(String desc, String regex, int index) {
		this.desc = desc;
		this.pattern = regex;
		this.index = index;
	}

	/**
	 * Retrieves the error index.
	 * 
	 * @return The approximate index in the pattern of the error, or <tt>-1</tt>
	 *         if the index is not known
	 */
	public int getIndex() {
		return index;
	}

	/**
	 * Retrieves the description of the error.
	 * 
	 * @return The description of the error
	 */
	public String getDescription() {
		return desc;
	}

	/**
	 * Retrieves the erroneous regular-expression pattern.
	 * 
	 * @return The erroneous pattern
	 */
	public String getPattern() {
		return pattern;
	}

	private static final String nl = java.security.AccessController
			.doPrivileged(new GetPropertyAction("line.separator"));

	/**
	 * Returns a multi-line string containing the description of the syntax
	 * error and its index, the erroneous regular-expression pattern, and a
	 * visual indication of the error index within the pattern.
	 * 
	 * @return The full detail message
	 */
	@Override
	public String getMessage() {
		StringBuffer sb = new StringBuffer();
		sb.append(desc);
		if (index >= 0) {
			sb.append(" near index ");
			sb.append(index);
		}
		sb.append(nl);
		sb.append(pattern);
		if (index >= 0) {
			sb.append(nl);
			for (int i = 0; i < index; i++)
				sb.append(' ');
			sb.append('^');
		}
		return sb.toString();
	}

}
